An electron is projected horizontally with a kinetic energy of 10 keV . A magnetic field of magnitude 1.0 10⁻⁷ T is present in the vertically upward direction. Will the electron deflect to the left or to the right of its original direction of motion?

Step-by-step solution

Let the direction of motion of the electron be along the +x -axis, so v = v i . Let the vertically upward direction be along the +y -axis, so B = B j . The magnetic force experienced by a moving charge is given by F = q( v B ) . For an electron, q = -e . Substituting the values, we get: F = -e(v i B j ) = -evB( i j ) = -evB k In a right-handed coordinate system, if +x is forward and +y is upward, the +z -axis ( k ) points to the left. Since the force is in the - k direction, the electron will deflect towards the ri